[GSAS-II] Calculating Particle size and Strain in GSAS2

[Shoaib Muhammad]

Dear All,

 

I want to get correct values of Particle Size and Strain by Rietveld
Refinement in GSAS2. I will briefly summarize what I have done so far. I
obtained the exact instrument parameter from HRPD beam line and used it.
Instrument parameter file was supposed to be used in Fullprof and has the
following text:

 

"Myresolution function

  0.000030   0.000050   0.000110 0 0 0"

 

In order to use it in GSAS2 instrument parameter file, I multiplied first
three term by 1803.4 and used as U V W and inserted 0 in X and Y of GSAS2
instrument parameters.

 

During the refinement I did not refine the "Instrument Parameters"  and
tried to match the peak shape by refining the "Crystal Size" and
"Microstrain" only, under Profile/Data tab. Refinement process proceeds but
I am unable to match the experimental peak profile with the calculated one
to a good extent. I have following queries and will be thankful if somebody
answer it.

 

1-      In old GSAS there were couple of Peak profile function like "Pseudo
Voith" and may be Pearson VII also. How can I select/refine these peak
Profile functions in GSAS2?

2-      Is it correct to fix U,V,W, X,Y in GSAS2 in-order to calculate
"Crystal Size" and "Microstrain"?

3-      Can I refine "Crystal Size" and "Microstrain" together?

4-      What does it mean by LGmin check box in Profile/Data tab?

5-      How to export the strain data to plot the image? I selected Mustrain
plot type, I can see the preview in plot window but can't export data. If
Mustrain is selected and I run the refinement, GSAS2 quits and I can't open
this file again. It always say "Python stopped working".

 

Thanks,

/Shoaib

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.aps.anl.gov/pipermail/gsas-ii/attachments/20140715/564dab99/attachment.html>